1. Field Of The Invention
This invention relates to a new and improved form of crystalline silicate ZSM-12, to a new and useful improvement in synthesizing said crystalline silicate and to use of the crystalline silicate prepared in accordance herewith as a catalyst for organic compound, e.g. hydrocarbon compound, conversion.
More particularly, this invention relates to an improved method of preparing crystalline silicate ZSM-12 whereby synthesis is facilitated and reproducible and the silicate product exhibits high purity and catalytic utility.
2. Discussion Of Prior Art
Crystalline silicate ZSM-12 and its conventional preparation are taught by U.S. Pat. No. 3,832,449, the entire disclosure of which is incorporated herein by reference. It has a distinctive X-ray diffraction pattern which identifies it from other known crystalline silicates.
U.S. Pat. No. 4,391,785 teaches a method for synthesis of zeolite ZSM-12 from a reaction mixture comprising, as a directing agent, a compound selected from the group consisting of dimethyl pyridinium halide and dimethyl pyrrolidinium halide. U.S. Pat. No. 4,296,083 claims synthesizing zeolites characterized by a constraint index of 1 to 12 and an alumina/silica mole ratio of not greater than 0.083 from a specified reaction mixture containing an organic nitrogen-containing cation provided by an amine identified as being selected from the group consisting of triethylamine, trimethylamine, tripropylamine, ethylenediamine, propanediamine, butanediamine, pentanediamine, hexanediamine, methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, benzylamine, aniline, pyridine, piperidine and pyrrolidine.
U.S. Pat. No. 4,151,189 claims a method for synthesizing zeolites ZSM-5, ZSM-12, ZSM-35 and ZSM-38 containing an organic nitrogen cation from a specified reaction mixture containing a primary amine having 2 to 9 carbon atoms as a directing agent. U.S. Pat. No. 4,112,056 teaches a synthesis method for ZSM-12 from a reaction mixture containing tetraethylammonium ions as directions agent. U.S. Pat. No. 4,452,769 claims a method for synthesizing ZSM-12 from a reaction mixture containing methyltriethylammonium ions as the directing agent. European Patent Application 13,630 claims synthesis of ZSM-12 from a reaction mixture containing a directing agent defined as an organic compound containing nitrogen and comprising "an alkyl or aryl group having between 1 and 7 carbon atoms, at least one of which comprises an ethyl radical".
Applicant knows of no prior art methods for preparing crystalline silicate ZSM-12 utilizing the present improved method.